It is proposed to develop glycoprotein subunit vaccines for immunization against parainfluenza virus infections. The experimental approach involves the study of the dose dependent antibody response and resistance to challenge infection following subcutaneous, intranasal or oral immunization with affinity purified parainfluenza 3 (PI 3) virus glycoproteins in hamsters. Suitable proportions of the purified glycoproteins, either before or after reconstitution into lipid vesicles, will be administered through the appropriate route for evaluation as a subunit vaccine. Once the optimal proportion of HN and F glycoproteins has been established in experimental animals, we will prepare suitable samples for administration to human volunteers. It is also proposed to clone the gene segments encoding envelope glycoproteins of parainfluenza 1 (PI 1) virus and to express the glycoprotein genes using baculovirus as a vector.